Coefficient of thermal expansion filler for vanadium-based frit materials and/or methods of making and/or using the same

ABSTRACT

Certain example embodiments relate to seals for glass articles. Certain example embodiments relate to a composition used for sealing an insulted glass unit. In certain example embodiments the composition includes vanadium oxide, barium oxide, zinc oxide, and at least one additional additive. For instance, another additive that is a different metal oxide or different metal chloride may be provided. In certain example embodiments, a composition may be combined with a binder solution that substantially or completely burns out by the time the composition is melted. In certain example embodiments, a CTE filler is included with a frit material. In certain example embodiments, a vacuum insulated glass unit includes first and second glass substrates that are sealed together with a seal that includes the above-described composition.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.13/339,463, filed Dec. 29, 2011, which is a continuation-in-part of U.S.application Ser. No. 13/238,358, filed Sep. 21, 2011, which is acontinuation-in-part of U.S. application Ser. No. 12/929,875, filed Feb.22, 2011, now U.S. Pat. No. 8,802,203 the entire contents of which areeach hereby incorporated by reference.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to coefficient ofthermal expansion (CTE) fillers for glass frit materials. Moreparticularly, certain example embodiments relate to fillers that areusable with vanadium-based frit materials. In certain exampleembodiments the fillers and frit materials may be used for glassarticles (e.g., for use in vacuum insulated glass or VIG units), and/ormethods of making the same, as well as articles including such fritmaterials and fillers and/or methods of making the same. In certainexample embodiments, frits with CTE filler(s) are used in connectionwith vacuum insulated glass (VIG) units, and/or a method is provided forsealing VIG units with the frits/seals. In certain example embodiments,material(s) in certain forms and/or particle sizes of for a CTE fillermay be used.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Vacuum IG units are known in the art. For example, see U.S. Pat. Nos.5,664,395, 5,657,607, and 5,902,652, the disclosures of which are allhereby incorporated herein by reference.

FIGS. 1-2 illustrate a conventional vacuum IG unit (vacuum IG unit orVIG unit). Vacuum IG unit 1 includes two spaced apart glass substrates 2and 3, which enclose an evacuated or low pressure space 6 there between.Glass sheets/substrates 2 and 3 are interconnected by peripheral or edgeseal of fused solder glass 4 and an array of support pillars or spacers5.

Pump out tube 8 is hermetically sealed by solder glass 9 to an apertureor hole 10 which passes from an interior surface of glass sheet 2 to thebottom of recess 11 in the exterior face of sheet 2. A vacuum isattached to pump out tube 8 so that the interior cavity betweensubstrates 2 and 3 can be evacuated to create a low pressure area orspace 6. After evacuation, tube 8 is melted to seal the vacuum. Recess11 retains sealed tube 8. Optionally, a chemical getter 12 may beincluded within recess 13.

Conventional vacuum IG units, with their fused solder glass peripheralseals 4, have been manufactured as follows. Glass frit in a solution(ultimately to form solder glass edge seal 4) is initially depositedaround the periphery of substrate 2. The other substrate 3 is broughtdown over top of substrate 2 so as to sandwich spacers 5 and the glassfrit/solution there between. The entire assembly including sheets 2, 3,the spacers, and the seal material is then heated to a temperature ofapproximately 500° C., at which point the glass frit melts, wets thesurfaces of the glass sheets 2, 3, and ultimately forms hermeticperipheral or edge seal 4. This approximately 500° C. temperature ismaintained for from about one to eight hours. After formation of theperipheral/edge seal 4 and the seal around tube 8, the assembly iscooled to room temperature. It is noted that column 2 of U.S. Pat. No.5,664,395 states that a conventional vacuum IG processing temperature isapproximately 500° C. for one hour. Inventors Lenzen, Turner and Collinsof the '395 patent have stated that “the edge seal process is currentlyquite slow: typically the temperature of the sample is increased at 200°C. per hour, and held for one hour at a constant value ranging from 430°C. and 530° C. depending on the solder glass composition.” Afterformation of edge seal 4, a vacuum is drawn via the tube to form lowpressure space 6.

The composition of conventional edge seals are known in the art. See,for example, U.S. Pat. Nos. 3,837,866; 4,256,495; 4,743,302; 5,051,381;5,188,990; 5,336,644; 5,534,469; 7,425,518, and U.S. Publication No.2005/0233885, the disclosures of which are all hereby incorporatedherein by reference.

Unfortunately, the aforesaid high temperatures and long heating times ofthe entire assembly utilized in the formulation of edge seal 4 areundesirable. This is especially the case when it is desired to use aheat strengthened or tempered glass substrate(s) 2, 3 in the vacuum IGunit. As shown in FIGS. 3-4, tempered glass loses temper strength uponexposure to high temperatures as a function of heating time. Moreover,such high processing temperatures may adversely affect certain low-Ecoating(s) that may be applied to one or both of the glass substrates incertain instances.

FIG. 3 is a graph illustrating how fully thermally tempered plate glassloses original temper upon exposure to different temperatures fordifferent periods of time, where the original center tension stress is3,200 MU per inch. The x-axis in FIG. 3 is exponentially representativeof time in hours (from 1 to 1,000 hours), while the y-axis is indicativeof the percentage of original temper strength remaining after heatexposure. FIG. 4 is a graph similar to FIG. 3, except that the x-axis inFIG. 4 extends from zero to one hour exponentially.

Seven different curves are illustrated in FIG. 3, each indicative of adifferent temperature exposure in degrees Fahrenheit (° F.). Thedifferent curves/lines are 400° F. (across the top of the FIG. 3 graph),500° F., 600° F., 700° F., 800° F., 900° F., and 950° F. (the bottomcurve of the FIG. 3 graph). A temperature of 900° F. is equivalent toapproximately 482° C., which is within the range utilized for formingthe aforesaid conventional solder glass peripheral seal 4 in FIGS. 1-2.Thus, attention is drawn to the 900° F. curve in FIG. 3, labeled byreference number 18. As shown, only 20% of the original temper strengthremains after one hour at this temperature (900° F. or 482° C.). Such asignificant loss (i.e., 80% loss) of temper strength may be undesirable.

As seen in FIGS. 3-4, the percentage of remaining tempering strengthvaries based on the temperature that is exposed to the tempered glass.For example, at 900° F. only about 20% of the original temper strengthremains. When the temperature that the sheet is exposed to is reduced to800° F., about 428° C., the amount of strength remaining is about 70%.Finally, a reduction in temperature to about 600° F., about 315° C.,results in about 95% of the original temper strength of the sheetremaining. As will be appreciated, it is desirable to reduce any temperstrength losses as a result of exposing a tempered sheet of glass tohigh temperatures.

As noted above, the creation of VIG units includes the creation of ahermetic seal that can withstand the pressure applied from the vacuumcreated on inside of the unit. As also discussed above, the creation ofthe seal may conventionally involve temperatures of at or above 500° C.These temperatures are required in order to obtain a high enoughtemperature in order for the frit material used for the seal to melt andform the required seal for the VIG units. As shown above, such atemperature can result in a strength reduction for VIG units usingtempered glass.

One conventional solution to sealing glass substrates together is to usean epoxy. However, in the case of VIG units, epoxy compositions may beinsufficient to hold a seal on a vacuum. Furthermore, epoxies may besusceptible to environmental factors that may further reduce theireffectiveness when applied to VIG units.

Another conventional solution is to use a frit solution that containslead. As is known, lead has a relatively low melting point. Accordingly,temperatures for sealing the VIG units may not need to be as high forother frit materials, and thus the tempering strength of tempered glasssubstrates may not be reduced by the same amount required for other fitbased materials. However, while lead based frits may resolve the abovestructural issues, the usage of lead in the frit may create newproblems. Specifically, the health consequences to the population forproducts that contain lead. Additionally, certain countries (e.g., inthe European Union) may impose strict requirements on the amount of leadthat can be contained in a given product. Indeed, some countries (orcustomers) may require products that are completely lead-free.

As is known in the art, when a frit or sealing material is disposed ontoa substrate, the coefficient of thermal expansion (CTE) of the sealingmaterial may be different than that of the underlying substrate. Thismay create a CTE mismatch between the two materials. In such situations,as the temperature of the underlying substrate and the sealing materialincreases/decreases, the materials may respectively expand/shrink atdifferent rates. This may cause structural problems in a product inwhich the sealing material is disposed (e.g., bound or adhered) againsta substrate. For example, the sealing material may end up delaminatingfrom the underlying substrate and causing the product to fail (e.g., asthe VIG loses vacuum). As such failure is undesirable, a CTE filler maybe added to the sealing material to adjust its expansion rate to bringit closer to (or match) that of the underlying substrate.

For certain applications (e.g., a given frit/substrate combination), anappropriate CTE filler may be known and may simply be added to the fritto obtain a CTE match. However, certain types of frits/glass articlesmay not have known or acceptable CTE fillers (e.g., a known CTE fillermay contain lead above a certain amount), thus making it generallyunsuitable for some markets and/or non-compliant with certain standards.Accordingly, it will be appreciated that CTE fillers for certain typesof frit material, for example, a vanadium based frit material, may bedesirable.

It will also be appreciated that techniques for creating improved sealsfor glass articles are continuously sought after.

Furthermore, frit materials may sometimes include binder agents that areused to, for example, facilitate binding the various materials that makeup the frit. However, in certain instances the materials used in a fritmay have a melting temperature that is less than a burn out point for abinder that is used in the frit. In such situations, the incomplete burnoff of a binder may result in a porous frit seal, reduced frit to glassbonding due to, for example, carbon contamination in the frit, or othercharacteristics that may be undesirable for frit based seals.

Accordingly, it will be appreciated that there exists a need in the artfor binders, solvents, CTE fillers, etc., that may be used with fritmaterials, e.g., with frit materials that have a relatively reducedmelting point such as vanadium based frits (e.g., VBZ frits).

It also will be appreciated that there exists a need in the art forimproved seals and the like that can be integrated with tempered glassunits, such as, for example, VIG units. The seals may be designed toallow for reduced temperature sealing such that annealed or temperedglass can be sealed without detrimental impact on the properties of theglass.

In certain example embodiments, a frit material may provide glass tofrit bonding sufficient for VIG purposes (e.g., in terms of structuralstrength). In certain example embodiments, the provided frit may provideproper glass wetting properties. In certain example embodiments, thefrit may seal and have structural strength and a homogenous glassystructure to provide an adequate barrier to prevent vacuum degradationin example VIG units over a period of time.

In certain instances, improvements in melt flow may enable improved fitmatching to glass expansion and/or increase process tolerances to fritbead variations. Improved wetting and bonding properties of a fitmaterial may increase VIG yield by reducing bonding failures of the fritto the glass. A reduction in crystallization may additionally oralternatively facilitate a selected composition to meeting differentheating environments (e.g., an internal seal, an external seal, etc).

In certain example embodiments, a method of making a vacuum insulatedglass (VIG) unit is provided. First and second glass substrates areprovided in substantially parallel, spaced apart relation to oneanother, with a gap being defined between the first and secondsubstrates. A material is disposed proximate to the first and/or secondglass substrates, with the material comprising at least a frit materialand a coefficient of thermal expansion (CTE) material. Energy is appliedto the material so as to melt the material at a melting temperature. TheCTE material comprises elements that are substantially spherical inform, and said elements are between about 60 and 100 microns in size.The frit material is formed from a base composition includes ˜45-50%(Normalized Mole %) vanadium oxide, ˜23% (Normalized Mole %) bariumoxide, and ˜19-22% (Normalized Mole %) zinc oxide.

In certain example embodiments, a material is provided. A coefficient ofthermal expansion (CTE) material is substantially lead-free. A fritmaterial has a composition that includes: ˜45-50% (Normalized Mole %)vanadium oxide, ˜20-23% (Normalized Mole %) barium oxide, and ˜19-22%(Normalized Mole %) zinc oxide. The material has a first CTE value thatis within about 15% of soda lime silicate glass by virtue of the CTEmaterial's composition.

In certain example embodiments, a vacuum insulted glass (VIG) unit isprovided. First and second substantially parallel, spaced apart glasssubstrates are provided. An edge seal is provided around a periphery ofthe first and/or second substrates to form a hermetic seal therebetweenand at least partially defines a gap between the first and secondsubstrates. The gap is provided at a pressure less than atmospheric. Theedge seal is formed from the material, at least initially, according tothe techniques disclosed herein, e.g., so as to include vanadium,barium, and zinc, as well as at least 4 additives, and a CTE matchingmaterial.

In certain example embodiments, a method of making a material isprovided. A composition is provided to a holder, the compositioncomprising ˜45-50% (Normalized Mole %) vanadium oxide, ˜20-23%(Normalized Mole %) barium oxide, and ˜19-22% (Normalized Mole %) zincoxide. The composition is melted. The melted composition is cooledand/or allowed to cool so as to form an intermediate article. A base fitmaterial is creating from the intermediate article. The base fitmaterial is combined with a CTE filler material that is comprised ofparticles that are 150-170 mesh and substantially spherical in shape.

In certain example embodiments, a method of bonding a frit material to aglass substrate is provided. The frit material is combined with a CTEmaterial to form a combined material. The combined material is disposedon the substrate. The combined material is heated to a temperature ofless than about 400 degrees C. A coefficient thermal expansionassociated with the combined material is within 10% of a coefficient ofthermal expansion for the glass substrate when heat is applied to thecombined material. The frit material includes a composition comprising:˜45-50% (Normalized Mole %) vanadium oxide, ˜20-23% (Normalized Mole %)barium oxide, and ˜19-22% (Normalized Mole %) zinc oxide.

The features, aspects, advantages, and example embodiments describedherein may be combined in any suitable combination or sub-combination torealize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1 is a cross-sectional view of a conventional vacuum IG unit;

FIG. 2 is a top plan view of the bottom substrate, edge seal, andspacers of the FIG. 1 vacuum IG unit taken along the section lineillustrated in FIG. 1;

FIG. 3 is a graph correlating time (hours) versus percent temperingstrength remaining, illustrating the loss of original temper strengthfor a thermally tempered sheet of glass after exposure to differenttemperatures for different periods of time;

FIG. 4 is a graph correlating time versus percent tempering strengthremaining similar to that of FIG. 3, except that a smaller time periodis provided on the x-axis;

FIG. 5 is cross-sectional view of a vacuum insulated glass unitaccording to certain example embodiments;

FIG. 6 is a flowchart illustrating a process for making a vacuuminsulated glass unit with a frit material according to certain exampleembodiments;

FIGS. 7A-7D are graphs summarizing properties of compositions accordingto certain example embodiments;

FIGS. 8A-8C are graphs summarizing the quality of compositions accordingto certain exemplary embodiments;

FIG. 9 is a graph showing results when additional elements are added tocompositions according to certain example embodiments;

FIGS. 10A-10C show graphs summarizing impacts of additives being addedto vanadium based fits according to certain example embodiments;

FIGS. 11A-11C show graphs summarizing absorption in the visible andinfrared wavelengths for vanadium based frits according to certainexample embodiments;

FIGS. 12A-12C are graphs summarizing flow characteristics of examplefrit materials according to certain example embodiments;

FIG. 13 is a graph showing thermogravimetric analysis of certain examplebinding agents;

FIGS. 14A and 14B respectively show a heating profile graph and theexample frit materials melted according to the heating profile;

FIGS. 15A and 15B respectively show another heating profile graph andthe example frit materials melted according to the heating profile;

FIG. 16 shows yet another heating profile graph;

FIGS. 17-20 show example frit materials melted according to certainexample embodiments;

FIG. 21 is a flowchart illustrating a process for melting a fritmaterial onto a substrate according to certain example embodiments;

FIG. 22 shows a graph illustrating the delamination properties ofcertain example materials;

FIGS. 23A-23C show microscope images of example particles of certainexample CTE fillers; and

FIG. 24 is a flowchart illustrating a process for creating an articleaccording to certain example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

The following description is provided in relation to several exampleembodiments which may share common characteristics, features, etc. It isto be understood that one or more features of any one embodiment may becombinable with one or more features of other embodiments. In addition,single features or a combination of features may constitute anadditional embodiment(s).

Certain example embodiments may relate to glass units (e.g., VIG units)that include two glass substrates sealed with an improved seal, e.g., ofor including a vanadium-based frit material. In certain exampleembodiments an improved seal may include the following materials:vanadium oxide, barium oxide, and zinc oxide. In addition, certainexample embodiments may include one or more of the following compounds:Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO2,Tl2O3, Y2O3, SnF2, SnO2, CuCl, SnCl2, CeO2, AgCl, In2O3, SnO, SrO, MgO,MoO₃, CsCO₃, CuCl₂, and Al₂O₃.

FIG. 5 is cross-sectional view of a vacuum insulated glass unitaccording to certain example embodiments. VIG unit 500 may include firstand second glass substrates 502 a and 502 b that are spaced apart anddefine a space therebetween. The glass substrates 502 a and 502 b may beconnected via an improved seal 504, of or including a vanadium-basedfrit. Support pillars 506 may help maintain the first and secondsubstrates 502 a and 502 b in substantially parallel spaced apartrelation to one another. It will be appreciated that the CTE of theimproved seal 504 and the glass substrates 502 a and 502 b maysubstantially match one another. This may be advantageous in terms ofreducing the likelihood of the glass cracking, etc. Although FIG. 5 isdescribed in relation to a VIG unit, it will be appreciated that theimproved seal 504, of or including a vanadium-based frit may be used inconnection with other articles and/or arrangements including, forexample, insulating glass (IG) units and/or other articles.

FIG. 6 is a flowchart illustrating a process for preparing a fritmaterial to be used in making a vacuum insulated glass unit according tocertain example embodiments. In step 600, base compounds are combinedand disposed into an appropriate container (e.g., a heat resistantcontainer such as, for example, a ceramic container). In step 602, thecombined compound is melted. Preferably, the temperature to melt thecombined material may be at least 1000° C. In certain exemplaryembodiments, the combined compound is melted at 1000° C. for between 30to 60 minutes. In certain exemplary embodiments, the combined compoundis melted at 1100° C. for 60 minutes. In certain exemplary embodiments,the combined compound is melted at 1200° C. for 60 minutes. In certainexemplary embodiments, the melting temperature is a cycle that includes500° C. for 15 minutes, 550° C. for 15 minutes, 600° C. for 15 minutes,and a ramp up to 1000° C. for 60 minutes.

After the combined compounds are melted, the material may be cooled instep 604, e.g., to form a glass sheet. After cooling, the glass may becrushed or ground into fine particulates in step 606. In certain exampleembodiments, the size of the particulates may be no larger than about100 mesh. Once the glass is ground into a powder, it may be disposedbetween the substrates in step 608. In certain example embodiments, thepowder may be dispensed as a paste with a binder. Additional details onbinding and/or solvent agents that may be used in certain exampleembodiments are provided in greater detail below. Heat may then beapplied in step 610 to the glass substrate and the powder. In certainexample embodiments, the heat may be between 300° C. and 400° C., ormore preferably between 325° C. and 375° C. It will be appreciated thatwhen heat of the above temperatures is applied to tempered glass thatthe tempered glass may lose a reduced amount of strength versus whenheat of in excess of 350° C. is applied to the tempered glass. Thus,certain example embodiments preferably involve a frit meltingtemperature of less than 500° C., more preferably less than 425° C., andsometimes less than 350° C.

In certain example embodiments, the combined compounds include thefollowing materials: vanadium oxide, barium oxide, and zinc oxide.

FIGS. 7A-7D show graphs summarizing properties of compositions accordingto certain example embodiments.

The table below corresponds to the data shown in FIG. 7A with thosecompositions with a melt quality of less than 4 (on a scale of 0 to 5)omitted from the table.

TABLE 1 Normalized Moles of Batch Composition V₂O₅ BaO ZnO BaO/ZnO Bi₂O₃B₂O₃ Tg(C.) Tx1(C.) Rating 43.66% 9.87% 46.47% 0.21 320 410 4 39.01%13.25% 37.37% .35 2.18% 8.20% 312 430 4 47.33% 12.96% 24.41% 0.53 9.95%5.53% 305 380 4 50.24% 23.38% 21.39% 1.33 320 425 4 51.54% 26.26% 16.46%1.60 5.75% 320 410 4.5

The melts shown in FIG. 7A were applied to a microscope glass slide witha temperature of 375° C. applied for 15 minutes. FIG. 7B shows a graphthat includes the crystallization temperature (first crystallizationpeak—Tx1—of the above table) of the above melts. According to certainexemplary embodiments, a preferred temperature for Tx1 may be betweenabout 375° C. and 425° C., preferably about 400° C.

FIG. 7C shows the transition glass temperatures, Tg, compared the abovemelts. The graph showing exemplary data shows that Tg values betweenabout 290 C. and 335 C. may be preferred for the above compositions.

FIG. 7D includes the above melts in a graph showing the melt qualityversus the barium/zinc ratio.

FIGS. 8A-8C show graphs that summarize the quality of compositionsaccording to certain exemplary embodiments. FIG. 8A summarizes the V₂O₅percentage used in certain exemplary compositions. FIG. 8B summarizesthe BaO percentage used in certain exemplary compositions. FIG. 8Csummarizes the ZnO percentage used in certain exemplary compositions. Asshown in the illustrative graphs, a vanadium percentage of between about51% and 53% may be preferable according to certain example embodiments.

Below, tables 2A-2C show exemplary compositions according to certainexample embodiments. Additionally, examples 7-15 in the tablescorrespond to graphs 8A-8C. For the compositions shown in the belowtables, BaCO₃ factor of 1.287027979 was used to convert to a BaOresulting compound.

TABLE 2A Weights of Normalized Weight Batch Composition WeightPercentage Weight for 25 grams Percentage Ex. V₂O₅ BaO ZnO Normal V₂O₅BaO ZnO V₂O₅ BaO ZnO 1 60 30 10 0.23 13.800 8.880 2.300 55.24 35.55 9.212 52.5 25 10 0.27 14.175 8.687 2.700 55.45 33.99 10.56 3 45 20 10 0.3113.950 7.980 3.100 55.73 31.88 12.39 4 45 10 20 0.32 14.400 4.118 6.40057.79 16.53 25.68 5 52.5 10 25 0.28 14.700 3.604 7.000 58.09 14.24 27.666 60 10 30 0.25 15.000 3.218 7.500 58.33 12.51 29.16 7 52.5 25 10 0.2412.600 7.722 2.400 55.45 33.99 10.56 8 57.5 25 10 0.25 14.375 8.0442.500 57.69 32.28 10.03 9 47.5 25 10 0.28 13.300 9.009 2.800 52.97 35.8811.15 10 52.5 27.5 10 0.26 13.650 9.202 2.600 53.63 36.15 10.22 11 57.527.5 10 0.25 14.375 8.848 2.500 55.88 34.40 9.72 12 47.5 27.5 10 0.2712.825 9.556 2.700 51.13 38.10 10.77 13 52.5 22.5 10 0.28 14.700 8.1082.800 57.40 31.66 10.93 14 57.5 22.5 10 0.26 14.950 7.529 2.600 59.6130.02 10.37 15 47.5 22.5 10 0.29 13.775 8.398 2.900 54.94 33.49 11.57

TABLE 2B Moles of Batch Normalized Moles Glass Ex. V₂O₅ BaO ZnO V₂O₅ BaOZnO Type 1 0.3037 0.1801 0.1132 50.87% 30.17% 18.95% amor- phous 20.3049 0.1722 0.1298 50.24% 28.38% 21.39% glassy 3 0.3064 0.1616 0.152249.41% 26.05% 24.54% amor- phous 4 0.3177 0.0838 0.3156 44.31% 11.68%44.01% amor- phous 5 0.3194 0.0722 0.3400 43.66% 9.87% 46.47% amor-phous 6 0.3207 0.0634 0.3584 43.19% 8.54% 48.27% amor- phous 7 0.30490.1722 0.1298 50.24% 28.38% 21.39% glassy 8 0.3172 0.1636 0.1233 52.51%27.08% 20.41% glassy 9 0.2912 0.1818 0.1370 47.74% 29.80% 22.46% glassy10 0.2949 0.1832 0.1255 48.85% 30.35% 20.80% glassy 11 0.3073 0.17430.1194 51.12% 29.00% 19.87% glassy 12 0.2811 0.1931 0.1323 46.35% 31.83%21.81% glassy 13 0.3156 0.1604 0.1344 51.70% 26.28% 22.01% glassy 140.3278 0.1521 0.1274 53.97% 25.05% 20.98% glassy 15 0.3021 0.1697 0.142149.20% 27.65% 23.15% glassy

The rating shown in Table 2C is based off of deposing the groundcomposition on a microscope glass slide and heating the composition atabout 375° C. for between 10 and 30 minutes.

TABLE 2C Example Tg (C.°) Tx2 (C.°) Tx2 (C.°) Tx1 − Tg Rating 1 280 330540 50 0.0 2 320 425 525 105 4.0 3 280 430 550 150 0.0 4 280 320 365 400.0 5 320 410 560 90 4.0 6 285 425 560 140 0.0 7 315 390 530 75 4.5 8295, 325 415 535 90 5.0 9 320 420 525 100 4.5 10 325 410 540 85 4.5 11315 395 530 80 4.5 12 330 415 560 85 4.0 13 315 400 530 85 5.0 14 305395 530 90 4.0 15 320 395 525 75 4.5

FIG. 9 shows a graph with results of adding additional elements (e.g.,Bi₂O₃ and B₂O₃) to a vanadium based frit. Corresponding data shown inFIG. 9 is also displayed below in Table 3.

TABLE 3 Ex. V2O5 BaO ZnO Bi2O3 B2O3 Tg(C.) Tx1(C.) DSC Responses 165.39% 14.87% 12.46% 0.00% 7.28% 320 430 medium weak 2 60.96% 13.86%11.61% 0.00% 13.57% 240 415 very weak 3 69.71% 15.85% 13.28% 1.16% 0.00%315 405 strong peaks 4 64.69% 14.71% 12.32% 1.08% 7.20% 325 440 veryweak 5 68.91% 15.67% 13.13% 2.29% 0.00% 320 410 medium weak 6 64.00%14.56% 12.19% 2.13% 7.12% 320 425 very weak 7 59.74% 13.59% 11.38% 1.99%13.30% 315 410 very weak 8 60.34% 13.72% 11.49% 1.00% 13.43% 315 400very weak 9 70.53% 16.04% 13.43% 0.00% 0.00% 315 380 strong peaks

In certain example embodiments, a strong DSC response may correspond toa good remelt quality. In certain example embodiments, the addition ofbismuth in concentrations of between about 0% and 3% may result inincreased remelt flow quality.

In certain example embodiments, a frit that includes V₂O₅, BaO, and ZnOmay further include one or more additives. In certain exampleembodiments, the additives may be between about 0.5% and 15% weight.According to certain example embodiments, the additives may be added toa base composition that includes between about 50% and 60% weight V₂O₅,27% and 33% weight BaO, and 9% and 12% weight ZnO.

Below, Tables 4A-4D show results of including additives to the basecomposition of V₂O₅, BaO, and ZnO. Table 4D shows the melt quality on ascale of about 0 to 5 for each of the compositions. FIGS. 10A-10C showgraphs corresponding to the data shown in the below tables. A BaCO3factor of 1.2870 was used to form the BaO used for the followingexamples.

TABLE 4A Weights (gm) Normalized Weights Ex V2O5 BaO ZnO Additive TypeAmount V2O5 BaO ZnO Additive 1 52.5 22.5 10 TeO2 2 14.175 7.819 2.7000.540 2 52.5 22.5 10 TeO2 4 13.650 7.529 2.600 1.040 3 52.5 22.5 10Ta2O5 5 13.650 7.529 2.600 1.300 4 52.5 22.5 10 Ta2O5 10 13.125 7.2402.500 2.500 5 52.5 22.5 10 Ti2O3 5 13.650 7.529 2.600 1.300 6 52.5 22.510 Ti2O3 10 13.125 7.240 2.500 2.500 7 52.5 22.5 10 SrCl2 2 14.175 7.8192.700 0.540 8 52.5 22.5 10 SrCl2 4 13.650 7.529 2.600 1.040 9 52.5 22.510 GeO2 1 14.175 7.819 2.700 0.270 10 52.5 22.5 10 GeO2 2 14.175 7.8192.700 0.540 11 52.5 22.5 10 CuO 1 14.175 7.819 2.700 0.270 12 52.5 22.510 CuO 2 14.175 7.819 2.700 0.540 13 52.5 22.5 10 AgO 1.5 14.175 7.8192.700 0.405 14 52.5 22.5 10 AgO 3 14.175 7.819 2.700 0.810 15 52.5 22.510 Nb2O5 3 14.175 7.819 2.700 0.810 16 52.5 22.5 10 Nb2O5 6 13.650 7.5292.600 1.560 17 52.5 22.5 10 B2O3 .8 14.175 7.819 2.700 0.216 18 52.522.5 10 B2O3 1.6 14.175 7.819 2.700 0.432

TABLE 4B Moles of Batch Normalized Weight Composition Percentage Addi-Ex V2O5 BaO ZnO Additive V2O5 BaO ZnO tive 1 56.17 30.99 10.70 2.140.309 0.157 0.131 0.013 2 55.00 30.34 10.48 4.19 0.302 0.154 0.129 0.0263 54.43 30.02 10.37 5.18 0.299 0.152 0.127 0.012 4 51.75 28.54 9.86 9.860.285 0.145 0.121 0.022 5 54.43 30.02 10.37 5.18 0.299 0.152 0.127 0.0116 51.75 28.54 9.86 9.86 0.285 0.145 0.121 0.022 7 56.17 30.99 10.70 2.140.309 0.157 0.131 0.013 8 55.00 30.34 10.48 4.19 0.302 0.154 0.129 0.0269 56.78 31.32 10.82 1.08 0.312 0.159 0.133 0.010 10 56.17 30.99 10.702.14 0.309 0.157 0.131 0.020 11 56.78 31.32 10.82 1.08 0.312 0.159 0.1330.014 12 56.17 30.99 10.70 2.14 0.309 0.157 0.131 0.027 13 56.48 31.1510.76 1.61 0.311 0.158 0.132 0.013 14 55.58 30.66 10.59 3.18 0.306 0.1550.130 0.026 15 55.58 30.66 10.59 3.18 0.306 0.155 0.130 0.012 16 53.8729.71 10.26 6.16 0.296 0.151 0.126 0.023 17 56.91 31.39 10.84 0.87 0.3130.159 0.133 0.012 18 56.42 31.12 10.75 1.72 0.310 0.158 0.132 0.025

TABLE 4C Normalized Moles Ex V2O5 BaO ZnO Additive Tg (C.) (Tx1(C.)Tx2(C.) Tx1 − Tg 1 50.57% 25.71% 21.53% 2.20% 315 400 525 85 2 49.48%25.16% 21.07% 4.30% 315 420 530 105 3 50.68% 25.76% 21.58% 1.99% 320 450130 4 49.69% 25.26% 21.16% 3.90% 320 450 530 130 5 50.71% 25.78% 21.59%1.92% 305 390 495 85 6 49.75% 25.29% 21.18% 3.77% 295 390 470 95 750.56% 25.70% 21.53% 2.21% 315 405 530 90 8 49.47% 25.15% 21.06% 4.32%315 400 530 85 9 50.83% 25.84% 21.64% 1.68% 315 395 530 80 10 49.99%25.41% 21.28% 3.31% 315 400 530 85 11 50.56% 25.71% 21.53% 2.20% 315 385525 70 12 49.47% 25.15% 21.06% 4.31% 320 395 545 75 13 50.61% 25.73%21.55% 2.12% 305 390 525 85 14 49.55% 25.19% 21.10% 4.16% 300 380 80 1550.68% 25.76% 21.58% 1.98% 315 425 550 110 16 49.69% 25.26% 21.16% 3.89%325 440 465 115 17 50.66% 25.75% 21.57% 2.02% 315 410 540 95 18 49.66%25.25% 21.14% 3.95% 320 405 545 85

TABLE 4D Melt Quality @ Melt Quality at Example 375 C., 15 min 350 C.,15 min 1 5.0 4.0 2 4.5 4.0 3 4.5 2.0 4 5.0 2.0 5 4.5 4.5 6 5.0 5.0 75.5+ 5.0 8 5.0 4.5 9 4.5 4.5 10 4.5 4.5 11 4.5 2.0 12 4.0 2.0 13 4.0 5.014 3.5 4.0 15 4.5 2.0 16 5.0 2.0 17 4.0 4.5 18 3.5 2.0

In certain example embodiments, the molar composition of an additive toa base composition higher than is shown in tables 4A-4D. Table 5A showsadditives with an increased additive amount (on a % mole basis). Thebase composition used with the additive amount may be based on, forexample, the base composition shown in Row 1 of Tables 4A-4D. Theadditives shown in Table 5, in the selected quantities displayed, mayimprove melt quality when compared to the above base composition. A melttype of Glassy indicates that a “button” of the compound melted onto aglass plate, forming a homogenous glassy structure. Sinter indicatesthat the compound (in a powder form) fused together, but remained in apowder form.

TABLE 5 Additive Melt Type (350 C. Adhesion to glass Example Type Amountfor 20 minutes) substrate. 1 CuCl 4.00% Glassy No Stick 2 SnCl2 3.99%Glassy No Stick 3 SnCl2 5.99% Glassy, Slight Flow Slight stick 4 SiO26.02% More Glassy No Stick 5 Al2O3 6.00% Glassy No Stick 6 CeO2 4.00%Sinter No Stick 7 TeO2 3.99% Glassy Slight stick 8 TeO2 6.01% GlassySlight stick 9 Tl2O3 3.99% Glassy, Slight Flow No Stick 10 Tl2O3 6.01%Glassy, Slight Flow No Stick

Accordingly, in certain example embodiments, additives of a relativelyincreased amount (e.g., versus those shown in FIG. 4) may be added to abase composition. In certain example embodiments, the additives mayinclude, for example, CuCl, SnCl₂, SiO₂, Al₂O₃, and TeO₂. It will beappreciated that toxic nature of thallium oxide (Tl₂O₃) may preclude itsuse in certain instances.

In certain example embodiments, two or more additives may be included ina base compound. Table 6 shows the results of adding two additives to anexemplary base composition. Table 6 includes example melts at 375 and350. Additionally, 13 mm buttons of the exemplary compounds were testedon a glass plate. The structural strength of the resulting exemplarycompound are also shown in the far right column.

TABLE 6 Amount Amount Melt Melt 13 mm 1 (Mole 2 (Mole Quality QualityButton Ex Add 1 Add 2 %) %) (375 C. 15-20 Min) (350 C. 15-20 Min) 350 C.20 Min Strength 1 TeO2 Al2O3 3.01 3.01 4.5 5.5 glassy Fractures 2 TeO2Al2O3 2.99 5.01 5 4 glassy Fractures 3 TeO2 Al2O3 4.02 3.01 6 5.5 glassyFractures 4 TeO2 Al2O3 3.99 5.00 5 4.5 glassy Fractures 5 TeO2 Al2O35.01 2.99 4.5 4.5 glassy Fractures 6 TeO2 Al2O3 5.00 5.00 5 4.5 glassyFractures 7 TeO2 SiO₂ 3.01 3.00 5 5.5 glassy Fractures 8 TeO2 SiO₂ 2.995.02 5 4.5 glassy Fractures 9 TeO2 SiO₂ 4.00 2.99 5 4 glassy Fractures10 TeO2 SiO₂ 3.99 4.99 5 4.5 Less Fractures glassy 11 TeO2 SiO₂ 5.002.99 4.5 4.5 Less Hard glassy 12 TeO2 SiO₂ 5.00 4.99 4.5 4.5 Less Hardglassy 13 SnCl2 Al2O3 3.01 3.01 5 6 more Hard glassy 14 SnCl2 Al2O3 3.005.01 5 5.5 glassy Hard 15 SnCl2 Al2O3 4.01 3.01 4.5 6 glassy Hard 16SnCl2 Al2O3 4.00 4.99 5.5 6 glassy Hard 17 SnCl2 Al2O3 5.00 2.99 5.5 5.5glassy Fractures 18 SnCl2 Al2O3 5.00 5.00 5.5 5.5 more Hard glassy 19SnCl2 SiO2 3.00 3.00 4.5 4.5 glassy Hard 20 SnCl2 SiO2 3.00 4.99 5 6glassy Hard 21 SnCl2 SiO2 4.00 2.99 6 6 glassy Fractures 22 SnCl2 SiO24.01 4.99 5.5 5.5 glassy Fractures 23 SnCl2 SiO2 5.00 2.99 5 5.5 glassyHard 24 SnCl2 SiO2 5.00 4.99 5.5 5.5 glassy Fractures 25 Al2O3 SiO2 3.013.00 4.5 4 less Hard glassy 26 Al2O3 SiO2 2.99 4.99 5 5.5 less Hardglassy 27 Al2O3 SiO2 4.00 2.99 4.5 4.5 less Hard glassy 28 Al2O3 SiO24.00 4.99 5 4.5 less Hard glassy 29 Al2O3 SiO2 5.01 2.99 5 4.5 less Hardglassy 30 Al2O3 SiO2 5.01 4.99 4 2 less Hard glassy

Accordingly, certain example may include two additives similar to thosefound in examples 3, 16, and 21 as shown in Table 6 (e.g., TeO2 withSiO2, SnCl2 with Al2O3, and SnCl2 with SiO2). In certain exampleembodiments, the addition of two or more additives may have beneficialresults on an exemplary base composition. For example the addition ofSiO2 to another additive may increase the strength of the overall frit.Alternatively, or in addition, TeO2 combined with other additives mayincrease the melt flow and glass wetting qualities of the frit whencompared to a base frit.

In certain example embodiments, the combination of SnCl2 with SiO2and/or Al2O3 may result in an increase in structural strength for theresulting frit material.

In certain example embodiments, one or more additives may be added to abase composition where the amount is between 1% and 10% by weight orbetween about 1% and 6% normalized moles for a batch. In certain exampleembodiments, additives may be added in a smaller amount, for examplebetween about 0.1% and 1% by weight. In certain example embodiments abatch for a base composition (in grams) may include V₂O₅ at 52.5, BaO at22.5, ZnO at 10. In certain example embodiments, additives added to theabove base composition may include: 1) TeO2 at 3.85 gm and Al2O3 at 1.84gm; 2) SnCl2 at 4.65 gm and Al2O3 at 3.12 gm; 3) SnCl2 at 4.55 gm andSiO2 at 1.08 gm. Correspondingly, the additives may then have anormalize weight percentage of: 1) TeO2 at 1.00 and Al2O3 at 0.48; 2)SnCl2 at 1.21 and Al2O3 at 0.81; 3) SnCl2 at 1.18 and SiO2 at 0.28.These examples may correspond to examples 3, 16, and 21 in the abovetable 6.

FIGS. 11A-11C show graphs illustrating absorption in the visible andinfrared wavelengths for vanadium based frits according to certainexample embodiments. As shown in the graphs, example vanadium basedfrits may have absorption of at least 90% across a substantial breath ofthe visible and IR spectrum. In certain example embodiments theabsorption may be about 95%. As discussed in co-pending application Ser.No. 12/929,874, filed on Feb. 22, 2011, entitled “IMPROVED FRITMATERIALS AND/OR METHOD OF MAKING VACUUM INSULATING GLASS UNITSINCLUDING THE SAME”, the entire contents of which are incorporatedherein by reference, frit materials with high visible/IR absorption maybe advantageous.

FIG. 11A shows the absorption properties of a vanadium based frit withTeO₂ and Al₂O₃ used as additives (e.g., Ex. 3 of Table 6). FIG. 11Bshows the absorption properties of a vanadium based fit with SnCl₂ andAl₂O₃ used as additives (e.g., Ex. 16 of Table 6). FIG. 11C shows theabsorption properties of a vanadium based fit with SnCl₂ and SiO₂ usedas additives (e.g., Ex. 21 of Table 6).

In certain example embodiments, the application of IR energy to a fritmaterial may be based on a heating profile where the IR energy appliedto the frit varies over time. Exemplary heating profiles may be found inco-pending application Ser. No. 12/929,874, the entire contents of whichare incorporated herein by reference.

In certain example embodiments, a base composition may be augmented by 3or 4 additives. For example, a batch for a base composition (in grams)may include V₂O₅ at 52.5, BaO at 22.5, ZnO at 10. Accordingly, threeand/or more additives from among TeO2, SnCl2, Al2O3, and SiO2 may beselected to augment the base composition. The ranges (in grams) for theadditives may vary between 0 to 7.5 grams per additive. Thus, on anormalized molar percentage the above additives may be included atbetween 0% and 6%. Thus, the normalized molar percentage of a basecomposition may be V₂O₅ at between about 43% and 50%, BaO between about22% and 26%, ZnO between about 18% and 22%. In certain exampleembodiments, additives (on a normalized molar basis) of TeO2 at around2%, SnCl2 around 2%, Al2O3 around 2%, and SiO2 around 4% may be added tothe base composition.

The techniques, compositions, etc disclosed herein may be used othermethods and/or systems for forming a VIG unit. For example, a vanadiumbased frit may be used to form an edge seal of a VIG unit. Systems,apparatuses, and/or methods used for creating a VIG unit may bedescribed in co-pending application Ser. No. 12/929,876, filed on Feb.22, 2011, entitled “LOCALIZED HEATING TECHNIQUES INCORPORATING TUNABLEINFRARED ELEMENT(S) FOR VACUUM INSULATING GLASS UNITS, AND/ORAPPARATUSES FOR THE SAME”, the entire contents of which are herebyincorporated by reference.

Certain example embodiments may include three or more additives to abase composition that includes vanadium pentaoxide; barium carbonatethat coverts in whole or in part to barium oxide; and zinc oxide. Theabove three “base” frit elements may be included at 35-55% molar forV₂O₅, 15-35% for BaO, and 15-25% molar for ZnO or, more preferably,40-50% molar for V₂O₅, 20-30% for BaO, and 18-22% molar for ZnO.

Along with an example base frit composition, one or more additives maybe added. The additives may include, for example:

1) SnCl₂ at between 1-10% molar, which may help reduce glass softeningtemperatures and/or reduce crystallization in certain exampleembodiments;

2) CuCl₂ at between 1-5% molar, which may help reduce glass softeningtemperature in certain example embodiments;

3) MoO₃ at between 1-6% molar, which may help reduce glass softeningtemperatures in certain example embodiments;

4) TeO₂ at between 1-10% molar, which may help increase glass flowability and/or wetting to a substrate glass in certain exampleembodiments;

5) Ta₂O₅ at between 0.5-5% molar, which may help increase softeningtemperature and/or increase crystallization temperature in certainexample embodiments;

6) Nb₂O₅ at between 0.5-6% molar, which may help increase softeningtemperature and/or increase crystallization temperature in certainexample embodiments;

7) Al₂O₃ at between 0.5-5% molar, which may help increase softening,weathering ability, chemical durability, and/or mechanical strength incertain example embodiments;

8) SiO₂ at between 0.5-5% molar, which may help increase softening,weathering ability, chemical durability, and/or mechanical strength incertain example embodiments; and

9) CsCO₃ at between 0.5-4% molar, which may help increase melt flowand/or reduce wetting ability in certain example embodiments.

In certain example embodiments, four or more additives, more preferablysix or more additives may be added to the above base composition. Itwill be appreciated that as the number of the additives increases, theinteractions between the various additives may produce different resultsbased on the relative weighting of one or more additives (or the basecomposition). It also will be appreciated that the increased number ofadditives may create synergistic effects (e.g., in terms of glasssoftening temperature, flowability, and/or other adjustments) thatotherwise might not be observable.

In certain example embodiments, one or more additives may be introducedthrough the frit creation process rather than being expresslyintroduced. For example, additive ingredients may be introduced into afrit material as a result of firing the frit material in a crucible. Forinstance, some ingredients may be “leached” from the crucible and intothe fit material. In certain example embodiments, Al₂O₃ and SiO₂ may beleached by this process.

Tables 7-10 show example frit compositions according to certain exampleembodiments. The different tables each include one or more additivesthat are varied while the other ingredients are kept substantially thesame between the example compounds of the give table.

In tables 7A-7C, molybdenum oxide is varied between the examplecompounds; in tables 8A-8C tellurium oxide is varied between the examplecompounds; in tables 9A-9C cesium carbonate is varied between theexample compounds; and in tables 10A-10D tantalum oxide and niobiumoxide are varied between the example compounds.

Tables 7A, 8A, 9A, and 10A show the example frit compositions bynormalized weight percentage. Tables 7B, 8B, 9B, and 10B show theexample frit compositions by normalized mole percent. The values givenin tables 7-10 A and B are normalized to approximately 100% for showncompositions. For example, V₂O₅ from example 1 in table 7A is 54.88% byweight of the frit composition for the frit composition. Similarly, V₂O₅for the same example frit composition is shown as 49.76% mole of theresulting fit composition (e.g., from Table 7B). Thus, the normalizedweight and mole percentages may add up to about 100% for the examplefrit compositions shown in the various tables herein. Tables 7C, 8C, 9C,10C, and 10D show exemplary results for the example frit compositions.As can be seen in the results of the above noted tables (e.g., tables7-10), performance of one or more of the above examples may be improvedover a base frit material, or a frit material with only one additive asdiscussed above. For example, example frit materials 9 and 11 shown inTable 8 show good flow at 375 degrees C. (5 and 6.5, respectively).

TABLE 7A MoO₃ Examples Normalized Weight Percentage Example V₂O₅ BaO ZnOMoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 1 54.88 26.61 10.45 0.87 4.15 1.38 0.000.00 1.65 2 54.64 26.49 10.41 1.31 4.13 1.37 0.00 0.00 1.64 3 54.3926.38 10.36 1.75 4.11 1.37 0.00 0.00 1.64 4 54.15 26.26 10.31 2.19 4.101.36 0.00 0.00 1.63 5 53.91 26.14 10.27 2.63 4.08 1.36 0.00 0.00 1.62 653.67 26.02 10.22 3.07 4.06 1.35 0.00 0.00 1.62

TABLE 7B MoO₃ Examples Normalized Moles of Batch Composition Ex. V₂O₅BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 1 49.76% 22.24% 21.18% 0.99%4.29% 0.51% 0.00% 0.00% 1.02% 2 49.50% 22.12% 21.08% 1.50% 4.27% 0.51%0.00% 0.00% 1.02% 3 49.25% 22.01% 20.97% 2.00% 4.24% 0.51% 0.00% 0.00%1.01% 4 49.00% 21.90% 20.86% 2.50% 4.22% 0.51% 0.00% 0.00% 1.01% 548.75% 21.79% 20.75% 3.00% 4.20% 0.50% 0.00% 0.00% 1.00% 6 48.50% 21.67%20.65% 3.50% 4.18% 0.50% 0.00% 0.00% 1.00%

TABLE 7C MoO₃ Examples Test Results 375 C. Slides Slides 13 mm 350 C.375 C. button 400 C. 13 mm Ex. 15 min 15 min 20 min Results button 20min Results 1 5.0 5.5 12.39 glass 13.76 light haze 2 3.0 4.5 12.80 glass14.06 light haze 3 4.0 5.5 12.51 glass 14.14 light haze 4 4.5 5.0 13.08glass 14.22 light haze 5 5.5 5.0 12.93 glass 14.26 light haze 6 5.5 5.512.88 glass 14.50 light haze

TABLE 8A TeO₂ Examples Normalized Weight Percentage Example V₂O₅ BaO ZnOMoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 7 54.84 26.59 10.45 2.67 2.42 1.38 0.000.00 1.65 8 54.56 26.46 10.39 2.66 2.91 1.37 0.00 0.00 1.64 9 54.2926.33 10.34 2.65 3.39 1.37 0.00 0.00 1.63 10 54.02 26.19 10.29 2.63 3.881.36 0.00 0.00 1.63 11 53.74 26.06 10.24 2.62 4.37 1.35 0.00 0.00 1.6212 53.47 25.93 10.18 2.61 4.86 1.34 0.00 0.00 1.61 13 53.20 25.80 10.132.59 5.34 1.34 0.00 0.00 1.60 14 52.92 25.66 10.08 2.58 5.83 1.33 0.000.00 1.59

TABLE 8B TeO₂ Examples Normalized Moles of Batch Composition Ex. V₂O₅BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 7 49.61% 22.17% 21.12% 3.06%2.50% 0.51% 0.00% 0.00% 1.02% 8 49.36% 22.06% 21.01% 3.04% 3.00% 0.51%0.00% 0.00% 1.02% 9 49.11% 21.95% 20.91% 3.03% 3.50% 0.51% 0.00% 0.00%1.01% 10 48.85% 21.83% 20.80% 3.01% 4.00% 0.51% 0.00% 0.00% 1.01% 1148.59% 21.72% 20.69% 2.99% 4.50% 0.50% 0.00% 0.00% 1.00% 12 48.34%21.60% 20.58% 2.98% 5.00% 0.50% 0.00% 0.00% 1.00% 13 48.09% 21.49%20.47% 2.96% 5.50% 0.50% 0.00% 0.00% 0.99% 14 47.83% 21.38% 20.36% 2.95%6.00% 0.49% 0.00% 0.00% 0.98%

TABLE 8C TeO₂ Examples Test Results 400 C. Slides Slides 13 mm 350 C.375 C 375 C. 13 mm button Ex. 15 min 15 min button 20 min Results 20 minResults 7 5.5 6.0 12.89 glass 14.37 haze 8 3.0 6.5 13.08 glass 14.63light haze 9 3.0 5.0 13.38 glass 14.93 light haze 10 6.5 5.0 13.17 glass14.66 light haze 11 4.5 6.5 13.04 glass 14.72 glass 12 6.0 6.5 12.72glass 14.53 light haze 13 5.5 5.0 12.94 glass 14.59 light haze 14 5.56.0 13.24 glass 14.92 light haze

TABLE 9A CsCO₃ Examples Normaized Weight Percentage Example V₂O₅ BaO ZnOMoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ CsCO₃ 15 52.95 25.68 10.09 2.58 4.311.33 0.00 0.00 1.59 1.47 16 52.69 25.55 10.04 2.57 4.29 1.32 0.00 0.001.59 1.97 17 52.43 25.43 9.99 2.56 4.26 1.32 0.00 0.00 1.58 2.44 1852.17 25.30 9.94 2.54 4.24 1.31 0.00 0.00 1.57 2.92 19 51.91 25.17 9.892.53 4.22 1.31 0.00 0.00 1.56 3.41 20 51.65 25.05 9.84 2.52 4.20 1.300.00 0.00 1.55 3.89

TABLE 9B CsCO₃ Examples Normalized Moles of Batch Composition (%) Ex.V₂O₅ BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ CsCO₃ 15 48.23 21.55 20.532.97 4.47 0.50 0.00 0.00 0.99 0.75 16 48.11 21.50 20.48 2.96 4.46 0.500.00 0.00 0.99 1.00 17 47.99 21.45 20.43 2.96 4.45 0.50 0.00 0.00 0.991.25 18 47.87 21.39 20.38 2.95 4.44 0.50 0.00 0.00 0.99 1.50 19 47.7421.34 20.33 2.94 4.43 0.49 0.00 0.00 0.98 1.75 20 47.62 21.28 20.27 2.934.41 0.49 0.00 0.00 0.98 2.00

TABLE 9C CsCO₃ Examples Test Results 13 mm Slide Slide button - 350 C. -375 C. - 13 mm button - 400 C. Ex. 15 min 15 min 375 C. 20 min Results20 min Results 15 5.5 6.5 13.40 glass 14.88 haze 16 5.5 5.5 13.05 glass15.40 glass 17 4.0 6.5 13.60 glass 15.17 light haze 18 4.5 6.5 13.33glass 14.81 haze 19 6.0 4.5 13.28 glass 14.59 haze 20 4.5 7.0 13.97glass 16.36 light haze

TABLE 10A Ta₂O₅ and Nb₂O₅ Examples Normalized Weight Percentage ExampleV₂O₅ BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 21 53.87 26.12 10.26 2.633.37 1.34 0.00 0.00 2.41 22 53.42 25.90 10.18 2.60 3.34 1.34 0.00 0.003.22 23 52.98 25.69 10.09 2.58 3.31 1.33 0.00 0.00 4.01 24 53.59 25.9910.21 2.61 3.35 2.65 0.00 0.00 1.60 25 53.15 25.77 10.12 2.59 3.32 2.650.00 0.00 2.39 26 52.71 25.56 10.04 2.57 3.29 2.65 0.00 0.00 3.18 2752.28 25.35 9.96 2.55 3.27 2.63 0.00 0.00 3.97 28 52.86 25.63 10.07 2.583.30 3.97 0.00 0.00 1.59 29 52.43 25.43 9.99 2.56 3.28 3.94 0.00 0.002.38 30 52.00 25.21 9.90 2.54 3.25 3.94 0.00 0.00 3.16 31 51.57 25.019.82 2.51 3.22 3.93 0.00 0.00 3.93

TABLE 10B Ta₂O₅ and Nb₂O₅ Examples Normalized Moles of Batch CompositionEx. V₂O₅ BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 21 48.87% 21.84%20.81% 3.01% 3.48% 0.50% 0.00% 0.00% 1.50% 22 48.61% 21.73% 20.70% 3.00%3.46% 0.50% 0.00% 0.00% 2.00% 23 48.37% 21.62% 20.59% 2.98% 3.44% 0.50%0.00% 0.00% 2.50% 24 48.87% 21.84% 20.81% 3.01% 3.48% 1.00% 0.00% 0.00%1.00% 25 48.62% 21.73% 20.70% 3.00% 3.46% 1.00% 0.00% 0.00% 1.50% 2648.37% 21.62% 20.59% 2.98% 3.44% 1.00% 0.00% 0.00% 2.00% 27 48.12%21.51% 20.49% 2.96% 3.43% 1.00% 0.00% 0.00% 2.50% 28 48.62% 21.73%20.70% 3.00% 3.46% 1.50% 0.00% 0.00% 1.00% 29 48.37% 21.62% 20.59% 2.98%3.44% 1.50% 0.00% 0.00% 1.50% 30 48.12% 21.50% 20.49% 2.96% 3.43% 1.50%0.00% 0.00% 2.00% 31 47.87% 21.39% 20.38% 2.95% 3.41% 1.50% 0.00% 0.00%2.50%

TABLE 10C Ta₂O₅ and Nb₂O₅ Examples Test Results 13 mm Slide Slidebutton - 350 C. - 375 C. - 13 mm button - 400 C. Ex. 15 min 15 min 375C. 20 min Results 20 min Results 21 4.5 6.5 13.24 glass 15.21 glass 224.0 6.5 12.42 glass 14.50 glass 23 2.5 6.0 12.24 glass 14.55 glass 244.5 6.5 12.56 glass 14.47 glass 25 3.0 5.0 12.35 glass 14.16 glass 264.5 6.0 12.19 glass 14.88 glass 27 4.5 5.0 12.30 glass 14.48 glass 283.0 5.5 12.16 glass 14.34 glass 29 3.0 5.5 11.62 glass 14.07 glass 303.0 5.5 11.79 glass 14.20 glass 31 3.0 6.0 11.77 glass 13.96 glass

TABLE 10D Ta₂O₅ and Nb₂O₅ Examples Test Results Continued 13 mm button -Example 425 C. 20 min Result 21 16.07 Haze 22 15.86 Haze 23 16.08 lighthaze 24 14.79 Haze 25 15.99 Glass 26 16.40 light haze 27 16.15 lighthaze 28 15.33 Haze 29 15.55 Glass 30 15.71 light haze 31 14.57 Haze

In certain example embodiments, the use of Ta₂O₅ and/or Nb₂O₅ may helpreduce the crystallization of the frit material. As the percentage ofcontribution by such additives increases, the softening temperature(e.g., a temperature at which the frit material may flow) may alsoincrease. In certain example embodiments, such properties may bedesirable for a tip off seal in a VIG unit (e.g., sealing the vacuumhole in a VIG unit).

Frit materials used for tipping off a vacuum hole may have differentdesirable properties than frit materials for a perimeter seal for a VIGunit. For example, a frit material used in a tip off seal may becompletely or substantially exposed to IR and therefore may reach ahigher temperature than that of a perimeter seal. Conversely, theperimeter seal may have the glass absorb some percentage of the SWIRdirected at the frit of a perimeter seal (e.g., 10%-30% of the SWIR).Thus, an exemplary frit material (e.g., example 21) may be used for aperimeter seal while example 26 may be used for tip off seal.

As shown in Table 10D, the example fit compositions may provideincreased resistance, or greater tolerance, to crystallization. Theexample compositions shown in Tables 7-10 were done in an aluminacrucible. With such a crucible, a certain amount of Al₂O₃ and SiO₂ maybe “leached” from the crucible during the frit preparation process.Thus, while Al₂O₃ and SiO₂ may not be shown in the above tables 7-10,these additives (or others depending on the crucible type) may yet bepresent in the frit composition due to the leaching process from thecrucible. The leaching of Al₂O₃ and SiO₂ may be a result of melting orfiring the frit compositions at certain temperatures (e.g., 800 C.degrees C., 1000 degrees C., etc). Different firing temperatures and/ordifferent lengths of time of firing may affect the amount of materialleached from the crucible. The variation of Al₂O₃ and SiO₂ may changethe frit performance for sealing at 375 degrees C. and 400 degrees C.

In certain example embodiments, Al₂O₃ may be included in a frit materialat between 0% and 2% normalized moles by composition, or at a normalizedweight percentage between 0% and 1.2%, or more preferably about 0.8%.SiO₂ may be included at between 1 and 5% normalized mole by compositionand/or between about 0.5 and 2% by weight, and more preferably about1.2% by normalized weight. The inventor has determined that in certaininstances, having SiO₂ or Al₂O₃ in amount greater than about 2-5%,resulted in undesirable flow qualities of the frit composition. Inparticular, when bonding to an example glass substrate, in certaininstances, higher percentages of SiO₂ or Al₂O₃ (e.g., in excess of 2 or4%) resulted in concrete like qualities for the final fit composition.

Table 11 shows example results in a platinum crucible. Such a cruciblemay reduce or even prevent the leaching of excess additives during thefiring process of the frit material.

TABLE 11 Platinum Crucible - Normalized Moles (%) V₂O₅ BaO ZnO CuClSnCl₂ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 44.56 21.96% 18.21% 1.42% 4.66% 3.88%0.47% 1.19% 2.73% 0.93% 44.25 21.81% 18.09% 1.41% 4.62% 3.85% 0.46%1.20% 3.38% 0.92% 43.95 21.66% 17.96% 1.40% 4.59% 3.83% 0.46% 1.19%4.05% 0.91% 44.38 21.87% 18.14% 1.41% 4.64% 3.86% 0.46% 1.60% 2.71%0.92% 44.08 21.72% 18.02% 1.40% 4.61% 3.84% 0.46% 1.59% 3.36% 0.92%43.78 21.57% 17.89% 1.39% 4.57% 3.81% 0.46% 1.58% 4.03% 0.91% 44.2021.78% 18.07% 1.41% 4.62% 3.85% 0.46% 1.99% 2.70% 0.92% 43.89 21.63%17.94% 1.40% 4.59% 3.82% 0.46% 1.99% 3.38% 0.91% 43.60 21.48% 17.82%1.39% 4.56% 3.80% 0.46% 1.98% 4.01% 0.91%

FIGS. 12A-12C are graphs summarizing flow characteristics of examplefrit materials according to certain example embodiments.

FIG. 12A shows that, at 375 degrees C., increasing Ta₂O₅ percentage maycause an increase in the initial softening temperature and resultingreduction in the flow (e.g., the diameter of the 13 mm button) for theexample frit material. In certain example embodiments, increasing Nb₂O₅percentage may provide less of a reduction in flow. As noted above, afrit (e.g., Ex. 21) with this composition may be used for a perimeterseal of a VIG unit.

FIG. 12B shows that, at 400 degrees C., Ex. 21 has improved flowcharacteristics. For example, with 1.0% Ta₂O₅, the frit flows well.

FIG. 12C shows, at 425 degrees C., Ex. 21 continuing to flow at highertemperatures, although, as shown above in Table 10D, the fritcomposition may become crystallized at such a temperature. However, Ex.26 may continue to have good flow and has only a slight crystallization.Accordingly, Ex. 26 may continue to flow at higher temperatures.

As discussed herein, a binding agent may be applied to (or combinedwith) a frit material (e.g., a frit material based on the materialsdescribed herein). The inventor of the instant application hasrecognized that the reduced melting temperatures of certain example fritmaterials may provide for melting points that are less than the burnouttemperature for certain types of binding agents that may be used inconjunction with the frit material. It is noted the following tests wereperformed using Ex. 26 as the frit composition, although the other fritcompositions disclosed herein are expected to have similar performancecharacteristics, unless otherwise specifically noted below. It also isnoted that a CTE matching material may be added in certain instances.One example is GM31682 available from Schott, which was added at 6.9 wt.% in conducting the following tests.

FIG. 13 is a graph showing a thermogravimetric analysis (TGA) of certainexample binding agents. The TGA analysis was performed in nitrogen and,as can be seen, the example “QPAC” binding agents (discussed in moredetail below) has a burn range that is approximately 100° C. lower thanother binders in the cellulose family of compounds.

In certain example embodiments, the following example binder materialsmay be used in conjunction with certain fit materials.

EXAMPLE 1

A methyl cellulose polymer binder. Example 1 included 0.75 wt % methylcellulose (400 cps molecular weight polymer) in DI water. TGA analysisof this material indicated a burn out of the binder at around 320-380°C.

EXAMPLE 2

A polyethylene carbonate binder, for example, [CH₂CH₂OCO₂]_(n) orC₃H₄O₃. One example of such a binder is available under the materialtrade name QPAC® 25 from Empower Materials Inc. It will be appreciatedthat other carbonate inclusive binder materials may be used in certainexample embodiments.

EXAMPLE 3

A polypropylene carbonate binder, for example, [CH₃CHCH₂OCO₂]_(n) orC₄H₆O₃. One example of such a binder is available under the materialtrade name QPAC® 40 from Empower Materials Inc. As noted above, in FIG.13, TGA analysis of these examples 2 and 3 indicated that the burnout ofthe binder material may be around 250-275° C.

The examples shown in FIGS. 14B, 15B, 16B, and 17-19 included a 5:1(gram) ratio frit-to-binder solution. These were dried into layers onmicroscope slides, and the slides were placed on a 71/38 coated glass.It will be appreciated that this ratio of fit to binder solution isgiven by way of example and that other ratios may be used. For example,the ratio may be between ratios of 4:1 and 6:1.

FIGS. 14A, 15A, and 16 are temperature vs. time graphs that each showvarious temperatures at varying times of an example fit material, a ducttemperature (e.g., where the IR energy is applied), and two glasssubstrates that are respectively coated (e.g., with a low-E coating) andnon-coated (e.g., “clear”).

FIGS. 14A and 14B respectively show a heating profile graph and examplefrit materials melted according to the heating profile of FIG. 14A. Theheating profile reflected in the graph of FIG. 14A included anapproximately 1 minute hold time 1402 at around 270-275° C. Subsequentto this hold time, the temperature was increased to a frit meltingtemperature. The ramp time for this increase may be between 1.8 and 2.3minutes or, more preferably, about 2.1 minutes.

FIG. 14B shows example frit materials that include different bindingagents. The melted fit material 1410 included the above noted example 2binding agent, whereas the melted frit material 1412 included the abovenoted exampled 1 binding agent. Frit 1410 had properties that includedbeing fused and porous, not glassy, and/or delaminating from thesubstrate. Frit 1412 had properties that included being rough and poorlyfused, not glassy, and/or delaminating from the substrate.

FIGS. 15A and 15B respectively show another heating profile graph andthe example melted frit materials according to the heating profile. Theheating profile reflected in the graph of FIG. 15A included anapproximately 1 minute hold time 1502 at around 265-275° C. Subsequentto this hold time, the temperature was increased to a frit meltingtemperature. The ramp time for this increase may be between 4.3 and 5.7minutes, more preferably between about 4.5 and 5.2, and even morepreferably between about 4.7 and 5 minutes. It will be appreciated thatsuch an increased ramp time (e.g., over the example shown in FIG. 14A)may be achieved by reducing the IR voltage related to the energy appliedto the frit material. For example, the voltage may be reduced from about80% to around 50%. It will be appreciated that such percentages may beadjusted depending on the energy output of the heating elements involvedin the melting process.

FIG. 15B shows example frit materials that include different bindingagents. The melted frit material 1510 included the above noted example 2binding agent, whereas the melted frit material 1512 included the abovenoted exampled 1 binding agent. Frit 1410 had properties that includedhaving a glossy appearance (e.g., an increase over the frits shown inFIG. 14B) while being rough with no flowed look and delaminating fromthe substrate. Frit 1512 had properties that included being rough andcracking (e.g., indicating the binding agent is still present) and/ordelaminating from the substrate. Such results may indicate that thebinding agent is still present in the example frit material.

FIG. 16 shows yet another heating profile graph that may be used forapplying energy to a fit material disposed onto a substrate. The heatingprofile reflected in the graph of FIG. 16A included an approximately 5minute hold time 1602 at around 270-275° C. According to certain exampleembodiments, the hold time may be between about 235-290° C. Subsequentto this hold time, the temperature was increased to a frit meltingtemperature (e.g., 380-400° C. or less than 400° C.). The ramp time forthis increase may be between 2 and 3 minutes, more preferably betweenabout 2.2 and 2.8, and even more preferably about 2.4 minutes.

FIGS. 17-20 shows example frit materials that include different bindingagents melted as a result of applying exemplary heating profiles. Fritmaterials 1702, 1802, 1902, and 2002 are based on a frit material thatincludes the above noted example 2 binding agent. Frit materials 1704,1804, 1904, and 2004 are based on a frit material that includes theabove noted example 3 binding agent. Frit materials 1706, 1806, 1906 and2006 are based on a frit material that includes the above noted example1 binding agent.

In FIG. 17, the heating profile used included about a 5 minute hold timeat around 275° C. with a subsequent 5 minute ramp time to seal (e.g., tothe melting temp of the fit material) was used. Frit materials 1702 and1704 both had good flow and solid bonds to the respective substrates.However, frit material 1706 was rough and not glassy and delaminatedfrom the substrate.

In FIG. 18, the heating profile used included about a 5 minute hold timeat around 275° C. with a subsequent 5 minute ramp time to seal (e.g., tothe melting temp of the frit material) was used. Frit materials 1802 and1804 both had good flow, but delaminated some from the substrate. Fritmaterial 1806 completely delaminated from the substrate. Also, while theedges of the frit may have melted, the roughness of the frit still waspresent in the melted version.

In FIG. 19, the heating profile used included about a 5 minute hold timeat around 275° C. A subsequent 2.3 minute ramp time to seal (e.g., tothe melting temp of the fit material) was used. Frit materials 1902 and1904 both had a good melt along with a good bond to the respectivesubstrates. Frit material 1906 had some melting along the edges, butstill lifted off the substrate. Frit materials 1 and 2 may then, alongwith the heating profile used in FIG. 19, be applied to a glasssubstrate and may be used to form a VIG unit.

In FIG. 20, the heating profile used included about a 10 minute holdtime at around 275° C. A subsequent 2.3 minute ramp time to seal (e.g.,to the melting temp of the frit material) was used. Frit materials 2002and 2004 both had good melts and adhesion to the substrate. Fritmaterial 2006 had a relatively poor melt and completely lifted off thesubstrate slide.

While certain example embodiments may use a holding temperature ofaround 275° C., other temperatures between about 235° C. to 325° C., ormore preferably between about 260° C. and 285° C. may be used. Incertain example embodiments, a holding temperature may be less thanabout 300° C. In one example, a holding temperature of about 267° C. wasused. In certain example embodiments, the temperature may vary, orslowly increase during this time period (e.g., to hold under a certaintemperature or within a certain range for a period of time).

Furthermore, hold times using these and other hold temperatures may beused. For example, a hold time may be between 1 and 30 minutes, morepreferably between about 2 and 15 minutes, and even more preferablybetween about 5 and 10 minutes may be used. In certain exampleembodiments, the hold time may be less than 5 or 10 minutes.

The named inventor of the instant application determined that in certaininstances a burnout time that is too short (e.g., less than a minute)may lead to leftover carbon residue. Such a characteristic may beundesirable under certain conditions. The named inventor also determinedthat in certain conditions, an increased hold time (e.g., in excess of30 minutes) may result in the frit material having a reduced bondstrength to an underlying substrate. Accordingly, it will be appreciatedthat a length of time used to “burn out” a binder solution may influencea quality of the frit (e.g., the frit to substrate seal). For example,certain example timeframes as disclosed herein may be used to reduce (orin some cases eliminate) the negative effects of the above undesirablecharacteristics.

Also, in certain example embodiments, the ramp time to the sealingtemperature may vary between about 1 minute and 10 minutes, morepreferably between about 2 and 5 minutes. Certain example embodimentsmay employ a ramp time of less than 5 minutes, or more preferably lessthan 3 minutes. Accordingly, certain example embodiments may userelatively reduced ramp times (e.g., times that are less than theholding temperature).

FIG. 21 is a flowchart illustrating a process for melting a fritmaterial onto a substrate according to certain example embodiments. Instep 2102, a frit that includes a binder is applied to a substrate. Instep 2104, the substrate is then disposed in an environment that raisesthe temperature of the frit material applied to the substrate to a firstlevel. Such a temperature may be between about 200° C. and 350° C., ormore preferably between about 250° C. and 300° C., or even morepreferably about 275° C.

In step 2106 the temperature of the frit material is held at arelatively stable level for a period of time, e.g., between about 1 and10 minutes, or about 5 minutes. The temperature of the frit is thenraised to the melting temperature of the frit in step 2108. This mayhappen over a period of less than about 5 minutes, more preferably lessthan about 3 minutes, or even more preferably about 2.3 minutes. In step2110, the substrate, frit, and other entities are then cooled. As aresult, the frit material may be bonded to the substrate, and the bindermaterial that was originally included with the frit may be substantiallyor completely burned off.

It will be appreciated by those skilled in the art that CTE adjustmentsmay be carried out on the overall frit material (e.g., the compound) forthe glass wetting and bonding properties of the frit to cooperate withan underlying substrate (e.g., a glass substrate). In certain exampleembodiments, CTE matching compounds may be added for these and/or otherpurposes.

One traditional CTE filler material that may be used with certainexample fit materials may be lead titanate. However, as discussed above,usage of lead as a CTE filler may be commercially impractical, e.g., dueto laws concerning the presence of lead in certain products (e.g.,windows). Accordingly, non-lead based CTE filler material may bedesirable in some cases.

In certain example embodiments, CTE filler material may be mixed in theform of a powder (e.g., spherical silica-vacuum bubbles) or microsphereswith a frit material to form a sealing material that is used on one ormore substrate(s).

For example, the following glass bubbles were tested with an examplevanadium based frit material. The type in table 12 refers to a type ofglass sphere available from the 3M Company.

TABLE 12 Example Glass Bubbles Crush Strength Density Thermal ParticleType (psi) (gm/cm³) Conductivity Size K37 3,000 0.37 0.124 45 S60 10,0000.6 0.2 30 S60 H 18,000 0.6 0.2 29 IM30K 28,000 0.6 0.2 15

As will be appreciated, the larger the bubble size the weakermechanically the glass is (e.g., as shown in the crush strength). Theinventor of the instant application determined that the IM30K exampleachieved results that were improvements over the other types in table12. Further, the inventor determined that increasing the ratio of glassbubble volume to frit material may reduce the amount of delaminating ofthe sealing material from a substrate. In other words, as the amount ofglass bubbles (e.g., in grams) to frit material is increased, the amountof delaminating to an example glass substrate may decrease. FIG. 22shows an example of the above noted materials and how they delaminatewhen applied to a substrate. The data points from left to right in thegraph represent increases in volume of the filler material used. Incertain instances, by percent of volume, the glass sphere volume may begreater than that of the fit volume. For example, the spheres (byvolume) may be 100% to 150% of the frit material.

In certain example embodiments, a CTE filler that is based on molybdenum(Mo) may be used. Molybdenum may have a linear ppm CTE of about 4.8. Theinventor of the instant application determined that molybdenum in aspherical form may perform with increased efficiency than othermolybdenum based particles. In certain example embodiments, shapes witha size of less than about 150 mesh or more even less than about 170 meshmay be used with certain example VBZ frit materials.

A CTE filler that includes molybdenum spheres of between about 0.8 and1.5 grams per 2.5 grams of frit material may produce improvedcompatibility with the base VBZ frit material and increase bond strengthto an example glass substrate. In certain example embodiments, 1.0 gramsof CTE filler per 2.5 grams of fit material may be used. In certainpreferred embodiments, a frit material may be combined with about a 1.2grams of molybdenum spheres (e.g., per 2.5 grams of frit material).

The inventor determined that use of spherical forms in CTE fillers mayincrease the effectiveness of restraining the frit matrix when comparedto random shapes of conventional particle fillers. In such instances,spherical sizes may correlate to how a frit material with CTE filler mayadhere to a glass substrate.

FIGS. 23A-23C show example microscope images of the spheres of certainexample molybdenum materials. Such materials may be obtained from, forexample, H. C. Starck and/or Alfa Aesar (a Johnson Matthey Company).FIG. 23A shows molybdenum spheres that are approximately 80 microns indiameter or major distance with some small variation in sizes, and theshapes being mostly round (e.g., spherical) and/or oblong. FIG. 23Bshows spheres that are larger than those in FIG. 23A and that generallyare in the 280-340 micron diameter or major distance range. As can beseen, the shapes in this molybdenum sphere example may be increasinglyerratic, ragged, and/or sharp. FIG. 23C shows molybdenum spheres thatare smaller than those of FIG. 23A. Here, the spheres are generallyround and between about 40 and 70 microns in diameter or major distance.

In certain instances, the size of a sphere may affect the CTE matchingproperties of a CTE material. It has been observed that small particles(e.g., <5 microns in diameter or major distance) tend to dissolve intothe frit during firing and contaminate the fit glass. It is noted thattypical CTE fillers tend to have a significant amount of particles <5microns in size. Additional dissolved compounds can upset thecomposition of the frit glass and change its sealing properties for theworse, unless it has a high tolerance for such contaminates (such astraditional lead fits). On the other hand, larger particles tend to haveless surface area per mass, so the amount of dissolved contaminate tendsto be significantly less. Thus, for example, a sphere size in theapproximate range of those spheres shown in FIG. 23A may be preferred.Accordingly, certain example CTE fillers may have spheres in a sizerange between about 60 and 100 microns, more preferably between about 70and 90 microns or, for example, about 80 microns in sphere diameter ormajor distance size.

It will be appreciated that not all of the spheres or material within agiven portion of CTE filler may fit such criteria (e.g., smaller/largerparticles or non-sphere shaped particles). Thus, certain exampleembodiments may be comprised of between 80% and 100% of the aboveidentified sphere sizes, with the remainder of the particles and/orspheres being outside such a sphere size (e.g., spheres/particles thatare greater than 100 microns or particles/spheres less than 60 microns).Additionally, not all of the “spheres” may be perfectly sphericallyshaped. Indeed, as shown in FIG. 23A some of the “spheres” may bepartially or substantially spherically shaped (e.g., oblong in shape orerratically, spherically shaped). Thus, the particles that are used incertain CTE fillers may be “substantially” spherical. For example, morethan half or 60% of the objects in a given CTE filler material may be“substantially” spherical, more preferably at least 80%, and even morepreferably at least 95%. In certain instances, a percentage ofspherically shaped elements in a CTE filler that are within a range of60 to 100 microns may comprise at least 90% by volume of the CTE filler,more preferably at least 95%, and even more preferably at least 98%.

It will be appreciated that small particles sizes (e.g., <1 micron) mayalso be present in the initial CTE filler material. Thus, in certaininstances for metals, heat may be used to consolidate the powderedmetals into spherical or oblong shapes. This process may decrease orotherwise eliminate the finer powder, e.g., <1 micron particles. Inother words, tiny particles may dissolve in the frit glass matrix andhave negative impacts on the sealing properties. Larger particles withless surface area per weight may have a more controlled and enhancedeffect on CTE expansion properties. Further, less spherical material maybe needed to obtain a similar CTE value than would a powder of the samematerial.

In certain instances, the surface chemistry of the spheres (or othershapes) may be modified to improved CTE matching properties and/or themechanical strength of the spheres (e.g., to withstand the stress of aVIG article).

In certain example embodiments, the following materials may be used inconjunction with a frit material for CTE matching the frit to a glasssubstrate: Cu₂P₂O₇×H₂O (e.g., Copper Pyrophosphate Hydrate); Mg₂P₂O₇(e.g., Magnesium Pyrophosphate); SnP₂O₇ (e.g., TinPyrophosphate—improved compatibility with at lower additions (e.g.,0.2-0.5 gm per 2.5 gm of frit material)); W (Tungsten powder—improvedcompatibility with frit materials at high addition levels (e.g., 1 to1.5 gm per 2.5 gm of frit material)); Fe/Ni 65:35 wt % (e.g., InvarAlloy—improved compatibility with frit materials at higher additionlevels (e.g., 0.6-0.8 gm per 2.5 gm of frit material)). Such materials(e.g., Invar) may be spherical in shape as the molybdenum materialdiscussed above. Further, certain materials (e.g., Invar) may havedecreased CTE—1.2 ppm—and may therefore lower the additional weightadded to a frit to obtain CTE matching. In certain instances, ceramicfillers may be used that are in spherical form (or substantiallyspherical form). In certain example embodiments, quartz may be used. Thequartz may be provided in the form of the spheres described herein. Asthe CTE of quartz is about 0.6, less material than other materialsdescribed herein may be needed in order to obtain a CTE match against agiven substrate. One aspect of certain example embodiments relates to afiller that is inert and does not react with the molten frit glassduring firing.

In certain example embodiments, Zirconium Tungstenate (e.g., ZirconiumTungsten Oxide or ZrW₂O₈) powder may provide acceptable CTE matching forcertain example frit materials with a soda lime float glass (e.g., withlinear CTE for the glass being between about 7.0-11.0 ppm). However, asZrW₂O₈ may be relatively expensive, such a CTE filler may becommercially impractical for some mainstream applications. However, itwill be appreciated that where cost is not an issue (or the overallprice of the CTE filler decreases), such a CTE filler may be used inconjunction with certain example frit materials described herein. Incertain example embodiments, a Zirconium Tungstenate based filler mayuse spherical shapes instead of particles (e.g., powder).

In certain example embodiments molybdenum spheres may be combined withglass bubbles (e.g., other particles). For example, 0.3-0.5 gm by weightof molybdenum spheres combined with 0.2-0.3 gm by weight of IM30K orbetween 0.15-0.35 by weight of ZrW₂O₈ and 0.2-0.3 gm of IM30K may beused according to certain example embodiments. In certain exampleembodiments, two or more of the discussed CTE fillers may be combined toform a combined CTE filler material.

FIG. 24 is a flowchart illustrating a process for creating an articleaccording to certain example embodiments. A CTE filler is combined withan exemplary frit material (e.g., a VBZ frit) in step 2402. The combinedmaterial is then disposed on a substrate in step 2404. For example, thesubstrate may be a soda lime float glass substrate. In certaininstances, e.g., the creation of the VIG unit, another substrate may beapplied with a gap between the two substrates. In any event, energy(e.g., IR energy) may be applied to the glass and/or the combinedmaterial to thereby melt the material in step 2406. After melting, thecombined material, and the substrate(s) or article may be cooled orallowed to cool in step 2408.

In certain example embodiments, the CTE of a frit material including anexemplary CTE filler may be within about 15% of the CTE of a substrate,more preferably within about 10%, even more preferably within about 5%,and even more preferably within about 3%. For instance, it is known thatglass has a CTE of 8.6 ppm, e.g., over a temperature range of about25-300 degrees C. It would be desirable to provide a CTE filler materialthat is less than or equal to this value. For instance, a CTE of 8.0 ppmover the same or similar range would be desirable. Doing so will keepthe glass in a state of compression, which is desirable.

Although certain example embodiments have been described as relating tospherical or generally spherical CTE fillers, other shapes may be usedin place of or together with such shapes. For instance, football,eye-shaped, cylindrical, elongated, whisker-shaped, and/or other typeparticles may be used. Such shapes may be symmetrical and/orsymmetrically curved in some example cases. In certain exampleembodiments, the shapes shown in FIGS. 23B and/or 23C may be used withsizes between, for example, 60-100 microns.

Moreover, it is to be understood that there may be some variation in aparticular size and/or shape material. However, in the aggregate, thematerial distributions should generally have the specified sizes/shapes.

The example embodiments described herein have been observed asexhibiting good compatibility with the specific example frit systemsdisclosed herein. For instance, the combination of the example CTEmatchers with the example frit materials disclosed herein have beenobserved as having good sealing properties such as glassy firedappearance and good frit-to-glass wetting and bond strength. Mechanicalstrength also has been found to be good. Some other commerciallyavailable CTE matching materials do not exhibit the same compatibility,strengths, etc., with the example frit materials disclosed herein.

It will be appreciated that one or more metal oxide, chloride, and/orfluoride additives may be used as additives in different embodiments ofthis invention. Furthermore, in certain example implementations, themetal oxide, chloride, and/or fluoride additives may be stoichiometricor sub-stoichiometric.

It is noted that the example embodiments discussed herein may be used inconnection with other applications such as, for example, MEMSapplications. In the MEMS context, the CTE filler may be increased tolower overall expansion to silicon and/or alumina. For example, 3 ppmCTE matcher with 40 wt % ZrW₂O₈ may be sufficient for the former, and 8ppm CTE with 35 wt % molybdenum-based spheres may be sufficient for thelatter.

In certain example embodiments, a method of making a vacuum insulatedglass (VIG) unit is provided. First and second glass substrates areprovided in substantially parallel, spaced apart relation to oneanother, with a gap being defined between the first and secondsubstrates. A material is disposed proximate to the first and/or secondglass substrates, with the material comprising at least a frit materialand a coefficient of thermal expansion (CTE) material. Energy is appliedto the material so as to melt the material at a melting temperature. TheCTE material comprises elements that are substantially spherical inform, and said elements are between about 60 and 100 microns in size.The frit material is formed from a base composition includes ˜45-50%(Normalized Mole %) vanadium oxide, ˜20-23% (Normalized Mole %) bariumoxide, and ˜19-22% (Normalized Mole %) zinc oxide.

In addition to the features of the previous paragraph, in certainexample embodiments, elements of the CTE material may comprisemolybdenum.

In addition to the features of either or the two previous paragraphs, incertain example embodiments, the elements may have an average diameteror major distance of between about 70 and 90 microns.

In addition to the features of any of the previous three paragraphs, incertain example embodiments, the elements may have a target diameter ormajor distance of about 80 microns.

In addition to the features of any of the previous four paragraphs, incertain example embodiments, the elements that are sustainably sphericalin form may include elements that are generally oblong.

In addition to the features of any of the previous five paragraphs, incertain example embodiments, the melting temperature may be less thanabout 400 degrees C.

In addition to the features of any of the previous six paragraphs, incertain example embodiments, the elements that are sustainably sphericalin form may comprise greater than 90%, by volume, of materials of theCTE material.

In addition to the features of any of the previous seven paragraphs, incertain example embodiments, the material may include a binder solutionthat includes polypropylene carbonate or polyethylene carbonate.

In addition to the features of any of the previous eight paragraphs, incertain example embodiments, the base composition may include at leastfour oxide-, chloride-, and/or fluoride-based additives.

In certain example embodiments, a material is provided. A coefficient ofthermal expansion (CTE) material is substantially lead-free. A fritmaterial has a composition that includes: ˜45-50% (Normalized Mole %)vanadium oxide, ˜20-23% (Normalized Mole %) barium oxide, and ˜19-22%(Normalized Mole %) zinc oxide. The material has a first CTE value thatis within about 15% of soda lime silicate glass by virtue of the CTEmaterial's composition.

In addition to the features of the previous paragraph, in certainexample embodiments, the CTE material may include molybdenum.

In addition to the features of either or the two previous paragraphs, incertain example embodiments, the CTE material may be comprised ofparticles that are substantially spherical in shape.

In addition to the features of the previous paragraph, in certainexample embodiments, the particles may include oblong shapes.

In addition to the features of any of the previous four paragraphs, incertain example embodiments, the CTE material may consist essentially ofelements that are between about 60 and 100 microns in diameter or majordistance.

In addition to the features of any of the previous five paragraphs, incertain example embodiments, a substantial majority of the elements inthe CTE material may be between about 70 and 90 microns in diameter ormajor distance.

In addition to the features of any of the previous six paragraphs, incertain example embodiments, the elements may be about 80 microns, onaverage.

In addition to the features of any of the previous seven paragraphs, incertain example embodiments, the CTE material may be substantiallycomposed of 150-170 mesh particles.

In addition to the features of any of the previous eight paragraphs, incertain example embodiments, a melting temperature of the material isless than about 400 degrees C.

In addition to the features of any of the previous nine paragraphs, incertain example embodiments, the composition may further include a leastsix additives selected from the group consisting of: Ta₂O₅, Ti₂O₃,SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO₂, Tl₂O₃, Y₂O₃, SnF₂,SnO₂, SnCl₂, CeO₂, AgCl, In₂O₃, SnO, SrO, MoO₃, CsCO₃, and Al₂O₃.

In certain example embodiments, a vacuum insulted glass (VIG) unit isprovided. First and second substantially parallel, spaced apart glasssubstrates are provided. An edge seal is provided around a periphery ofthe first and/or second substrates to form a hermetic seal therebetweenand at least partially defines a gap between the first and secondsubstrates. The gap is provided at a pressure less than atmospheric. Theedge seal is formed from the material, at least initially, according toany of the previous ten paragraphs.

In certain example embodiments, a method of making a material isprovided. A composition is provided to a holder, the compositioncomprising ˜45-50% (Normalized Mole %) vanadium oxide, ˜20-23%(Normalized Mole %) barium oxide, and ˜19-22% (Normalized Mole %) zincoxide. The composition is melted. The melted composition is cooledand/or allowed to cool so as to form an intermediate article. A basefrit material is creating from the intermediate article. The base fritmaterial is combined with a CTE filler material that is comprised ofparticles that are 150-170 mesh and substantially spherical in shape.

In addition to the features of the previous paragraph, in certainexample embodiments, the composition may include at least four additivesselected from the group consisting of: Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO,AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO₂, Tl₂O₃, Y₂O₃, SnF₂, SnO₂, SnCl₂, CeO₂,AgCl, In₂O₃, SnO, SrO, MoO₃, CsCO₃, and Al₂O₃.

In addition to the features of either or the two previous paragraphs, incertain example embodiments, the CTE filler material may comprisemolybdenum.

In certain example embodiments, a method of bonding a frit material to aglass substrate is provided. The frit material is combined with a CTEmaterial to form a combined material. The combined material is disposedon the substrate. The combined material is heated to a temperature ofless than about 400 degrees C. A coefficient thermal expansionassociated with the combined material is within 10% of a coefficient ofthermal expansion for the glass substrate when heat is applied to thecombined material. The frit material includes a composition comprising:˜45-50% (Normalized Mole %) vanadium oxide, ˜20-23% (Normalized Mole %)barium oxide, and ˜19-22% (Normalized Mole %) zinc oxide.

In addition to the features of the previous paragraph, in certainexample embodiments, the CTE material may comprise particles that are150-170 mesh.

In addition to the features of either or the two previous paragraphs, incertain example embodiments, the CTE material consists essentially ofparticles that are spherical in form.

In addition to the features of any of the previous three paragraphs, incertain example embodiments, the CTE material may comprise molybdenum.

As used herein, the terms “on,” “supported by,” and the like should notbe interpreted to mean that two elements are directly adjacent to oneanother unless explicitly stated. In other words, a first layer may besaid to be “on” or “supported by” a second layer, even if there are oneor more layers there between.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A vacuum insulated glass (VIG) window unit,comprising: first and second substantially parallel, spaced apartthermally tempered glass substrates; and an edge seal provided around aperiphery of the first and/or second thermally tempered glass substratesof the VIG window unit to form a hermetic seal therebetween and at leastpartially defining a gap between the first and second substrates,wherein the gap is provided at a pressure less than atmospheric, whereinthe edge seal is formed from edge seal material including (a) acoefficient of thermal expansion (CTE) material that is substantiallylead-free, and (b) a frit material having a composition comprising:Normalized Ingredient Mole % vanadium oxide ~45-50%, barium oxide~20-23%, and zinc oxide ~19-22%.

wherein the vanadium oxide, the barium oxide, and the zinc oxide are thethree largest elements making up the frit material composition, andwherein the edge seal material has a first CTE value that is withinabout 15% of soda lime silicate glass by virtue of the CTE material'scomposition.
 2. The VIG unit of claim 1, wherein the CTE materialcomprises elements that are substantially spherical in form and whereina plurality of said elements are between about 60 and 100 microns insize.
 3. The VIG unit of claim 2, wherein elements of the CTE materialcomprise molybdenum.
 4. The VIG unit of claim 2, wherein the elementshave an average diameter or major distance of between about 70 and 90microns.
 5. The VIG unit of claim 2, wherein the elements that aresustainably spherical in form include elements that are generallyoblong.
 6. The VIG unit of claim 1, wherein edge seal material is meltedin forming the edge seal, and wherein a melting temperature of the edgeseal material is less than about 400 degrees C.
 7. The VIG unit of claim2, wherein the elements that are sustainably spherical in form comprisegreater than 90%, by volume, of materials of the CTE material.
 8. TheVIG unit of claim 1, wherein a base composition of the frit materialincludes at least four oxide-, chloride-, and/or fluoride-basedadditives.
 9. A vacuum insulted glass (VIG) window unit, comprising:first and second substantially parallel, spaced apart thermally temperedglass substrates; and an edge seal provided around a periphery of thefirst and/or second thermally tempered glass substrates of the VIGwindow unit to form a hermetic seal therebetween and at least partiallydefining a gap between the first and second substrates, wherein the gapis provided at a pressure less than atmospheric, wherein the edge sealis formed from edge seal material including (a) a coefficient of thermalexpansion (CTE) material that is substantially lead-free, and (b) a fritmaterial having a composition comprising vanadium oxide, barium oxide,and zinc oxide; wherein the vanadium oxide, the barium oxide, and thezinc oxide are the three largest elements making up the frit materialcomposition; wherein the CTE material comprises elements that aresubstantially spherical in form and wherein a plurality of said elementsare between about 60 and 100 microns in size; and wherein the edge sealmaterial has a first CTE value that is within about 15% of soda limesilicate glass by virtue of the CTE material's composition.
 10. The VIGunit of claim 9, wherein elements of the CTE material comprisemolybdenum.
 11. The VIG unit of claim 9, wherein the elements have anaverage diameter or major distance of between about 70 and 90 microns.12. A vacuum insulated glass (VIG) window unit, comprising: first andsecond substantially parallel, spaced apart thermally tempered glasssubstrates; and an edge seal provided around a periphery of the firstand/or second thermally tempered glass substrates of the VIG window unitto form a hermetic seal therebetween and at least partially defining agap between the first and second substrates, wherein the gap is providedat a pressure less than atmospheric, wherein the edge seal is formedfrom edge seal material including (a) a coefficient of thermal expansion(CTE) material that is substantially lead-free, and (b) a frit materialhaving a composition comprising: Normalized Ingredient Mole % vanadiumoxide ~45-50%, barium oxide ~20-23%, and zinc oxide ~19-22%; and

wherein the vanadium oxide, the barium oxide, and the zinc oxide are thethree largest elements making up the frit material composition, andwherein the CTE material comprises elements that are substantiallyspherical in form and wherein a plurality of said elements are betweenabout 60 and 100 microns in size, and wherein the edge seal material hasa first CTE value that is within about 15% of soda lime silicate glassby virtue of the CTE material's composition.
 13. The VIG unit of claim12, wherein elements of the CTE material comprise molybdenum.
 14. TheVIG unit of claim 12, wherein the elements have an average diameter ormajor distance of between about 70 and 90 microns.
 15. The VIG unit ofclaim 12, wherein the elements that are sustainably spherical in forminclude elements that are generally oblong.
 16. The VIG unit of claim12, wherein edge seal material is melted in forming the edge seal, andwherein a melting temperature of the edge seal material is less thanabout 400 degrees C.
 17. The VIG unit of claim 12, wherein the elementsthat are sustainably spherical in form comprise greater than 90%, byvolume, of materials of the CTE material.
 18. The VIG unit of claim 12,wherein a base composition of the frit material includes at least fouroxide-, chloride-, and/or fluoride-based additives.